include use /* A circular helix of radius a and pitch 2πb is described by the following parametrisation: x(t) = a*cos(t), y(t) = a*sin(t), z(t) = b*t */ function b(pitch) = pitch/(TAU); function t(pitch, z) = z/b(pitch); function helix_curve(pitch, radius, z) = [radius*cos(deg(t(pitch, z))), radius*sin(deg(t(pitch, z))), z];